Remove dependency to libmediadrm from drm HAL

drm HAL has been using libmediadrm for android::SharedLibrary class and
android::PluginLoader class. This is a Treble violation since
libmediadrm is a framework-only library that is not available to
vendors.

To solve the problem, the two classes are copied into this directory
to form a small static library android.hardware.drm@1.0-helper.a.

Bug: 38302533
Test: mm under /hardware/interfaces/drm/1.0/default and
/hardware/interfaces/drm/1.0/vts/functional

Change-Id: I7b4e5cdb3bc815e971e0c3b7ec99ea86042e13eb
diff --git a/drm/1.0/default/DrmFactory.h b/drm/1.0/default/DrmFactory.h
index a008844..726bf97 100644
--- a/drm/1.0/default/DrmFactory.h
+++ b/drm/1.0/default/DrmFactory.h
@@ -19,7 +19,7 @@
 #include <android/hardware/drm/1.0/IDrmFactory.h>
 #include <hidl/Status.h>
 #include <media/drm/DrmAPI.h>
-#include <media/PluginLoader.h>
+#include <PluginLoader.h>
 #include <media/SharedLibrary.h>
 
 namespace android {
@@ -28,6 +28,7 @@
 namespace V1_0 {
 namespace implementation {
 
+using ::android::hardware::drm::V1_0::helper::PluginLoader;
 using ::android::hardware::drm::V1_0::IDrmFactory;
 using ::android::hardware::drm::V1_0::IDrmPlugin;
 using ::android::hardware::hidl_array;
@@ -53,7 +54,7 @@
             const hidl_string& appPackageName, createPlugin_cb _hidl_cb) override;
 
 private:
-    android::PluginLoader<android::DrmFactory> loader;
+    PluginLoader<android::DrmFactory> loader;
 
     DrmFactory(const DrmFactory &) = delete;
     void operator=(const DrmFactory &) = delete;